1. Field of the Invention
The present invention relates to a method of coating a substrate.
2. Background Information
A conventional automotive coating process typically includes the sequential application of coating compositions onto a substrate. For example, an electrodepositable coating composition, usually a cationic composition, is applied onto a pretreated substrate. The electrodepositable coating composition is then cured prior to application of a primer-surfacer coating composition over the electrodeposition coating. The primer-surface layer typically masks any surface defects present in the electrodeposition coating, thereby ensuring a smooth appearance of the subsequently applied top coatings to the coating layer system.
After the primer-surfacer coating composition has been applied onto the cured electrodepositable coating, the primer-surfacer coating is cured and sanded to remove surface defects. A color-enhancing and/or effect-enhancing basecoating composition is then applied onto the primer-surfacer coating. The basecoating is typically given a flash bake at a temperature and for a time sufficient to drive off excess solvents, but insufficient to cure the basecoating composition. A transparent or clear coating composition is then applied onto the uncured basecoating. This is commonly referred to as a wet-on-wet application. The basecoating composition and the transparent or clear coating composition are then cured together in a single step.
There is, however, a need for a coating process that reduces and/or eliminates that number of steps and/or coating compositions used during the coating process thereby reducing the time and cost issues typically associated with coating a substrate.